Stoker riser screw



2 Sheets-Sheet 1 s. G. JONES sTokER RIsER scREw Flled May 1, 1941 Nov. 2s, 1944.

Nov. 28, 1944.l s. G. JONES 2,363,968.

STOKER RISER SCREW Filed May 1, 1941 2 sheds-sheet 2 INVENTQR.

Mza-14 g4 Arron/Ens.

wardly and forwardly to an apron 24 integral therewith that overlies the bottom ofthe backwall opening to protect it from any possible `abrasion that might accidentally occur. The lower portion of the jet member is provided with passages connected by pipes 26 to a sourceof' Iluid under pressure, such as the steam in the locomotive boiler, and the inclined front wall of4 the jet member is provided with a plurality of jet `orices 2'! from which the steam issues for throwing coal forwardly across the grate. The inside of the jet member is` preferably divided by vertical partitions 28 (Fig. 2V) into several chambers to each of which steam is delivered by a separate pipe 26 controlled by a manually operable valve 29 so that the pressure in each chamber can be individually regulated to aid in giving control over fuel distribution.

The coal which .is'thrown upwardly by the steam jets is intercepted and directed forwardly in all directions by a fuel-deccting member 3| provided with guiding -ribs 38. The deflector is supported from its rear end by a horizontal shaft 32 extending therethrough and pivotally mounted .f

in lugs 33 depending from the top wall of the riser. The exposed end of the shaft is provided with` a lever 34 fory turning ,it in order to swing the deector in'a Vertical plane; and the lever is locked in adjusted positionsby any suitable means.

It is a feature of thisinvention thatthe forwardly moving stream 0f coal in the upper portion of the riser conduit is more or less leveled olf and spread laterally across the jet member fory substantially its full width. Accordingly, in the embodiment of the invention shown in Figs. 1, 2 and 3 the riser screw has a normal or main conveyor thread 4I that extends upwardly from the lower end ofthe screw hub 42 to a pointin the enlarged upper portion of the riser conduit several inches below the upper end of the hub which is above the jet member. Starting a short distance above theupper end of the main thread there is a short thread 43 that ,winds around the screw hub in the same direction as the main thread. The screw thus has between its two threads a portion of greatly vreduced diameter which' is free of threads located inthe enlarged portion of .the conduit behind the jetrmember. When coal that is, being elevated through the riser conduit by` the main thread 4I reaches this reduced portion of the screw there isno thread to carry the coalfarther andits feedfis therefore Agreatly vretarded so 'that instead-of moving ahead -a-t the same rate as the coal behind, it heaps-up into a pile that is-pushed forward by the -oncoming coal. The shortfiight 43 at the delivery'end of the screw digs into rthiswmound of coal and'spreads it laterally across the full width of the jet memberyso that instead of'a relatively narrow and deep stream of 'coal passing over the central "portion -of the .jet member with little or no coal passing over `its side `poi"- tions, the coal is more or less leveled off into a much thinner layer that passes over the jet mem` ber from' side to side.v `Asa `result,a more vuniform distribution of coal overthe grate 'rcan be obtained, and 'considerably less" stearnisW required Ascrew hub between its two threads with an enlargement 44 that tapers rearwardly.

With the riser screw shown in Fig. 3, which rotates Vin a clockwise direction, more coal will be delivered tothe left half of the jet member than to its' right half. This non-.uniform delivery can be compensated for to some extent by drilling the jet orices 21 at such angles that some of other thread.

those in thev left half of the jet member will throw coal from that side across to the .right half of the fire-box to make up for the deficiency there that otherwise might exist. The directions taken by steamissuing from the jets is illustrated in Fig. 3 by the broken lines in front of l the jet member.

In the modification shown in Fig. 4, instead of providing the screw with two spaced threads as previouslydescribed herein, a continuous single thread 46 extends from end to end of the hub but it is reduced materially in diameter at a point spaced from the upper end of the screw to retard the coal feed in order to permit the coal to mound up so that it can be spread laterally across a jet member by the upper flight Vof the screw. The same typel of continuous thread 46 is used in Fig. 5, but the delivery end portion of the screw hub is provided with an additional short thread 41 disposed about 180 from the In the Fig. .4 embodiment the deliveryend of the screw hub is provided with a forwardly and rearwardly tapered enlargement 48 that helps guide coal laterally away frcmfthe hub.:l

In the embodiment of my invention shown in Figs. 6 and 7, the delivery end portion of the screw hub is not providedwith a screw flight, but'is liared so that it resembles a cone 5 I .which directs the forwardly movingcoal toward thev sides of 'A thevjet member. This cone, maybe hollow, and

coal thatfalls in frontfof itiis moved over the central portion of thenjet member'bysteam issuing from a pipe 452 extendingaxially through the hub 'and connected at its-lower end inany'suit'- able mannerto the vsteam-supply'` of the locomo- The modication shownin Figs. 8 and/9 is simi; lar to that shown in`Figs. `6 and '7, but the ared end of thescrewhub is provided with radial slots 56y through which coal can 4pass 'tofreach' the central portion Aof thejet member. VThis'enlargetl endof the hub'may also 'be provided Witlra short thread-51 to aid'in feeding thetcoal': 'This thread preferably'winds around the 'hub in the direction opposite'to that of the mainthread SSandithereby cooperates with thev main thread in' produc"- ing a. substantially uniform delivery 'of coal on both sides of the screw in the vmanner-set' forth in my-said copending application.

A'As in the twopreceding embodimentsg'theform of my invention shown in Fig. 10 has' a main conveyorA threadll4 thatterminates short of the upper end ofthe screw hub 62, andthe delivery end portion ofthehub'is enlarged. vI-Iowevei, inthis vcase the 'enlargement is produced by providing the hub with several radialns" or varies 63 lthe' outer edges'iof whichflare forwardly. As the screw rotates, these vanes' push the heaped up coaliftowardsfthe" oppositg sidesof the jet member, but somecoal '.n'ves' straight' ahe'a'd between the vanes to the central portion of the jet member. The same general type of screw is shown in Figs. 12 and`13, except that onlyr two diametrically opposite vvaries liare` used and these are preferably curved as shown in Fig. 13.

- According to the provisions of the patent statutes, I have explained the principle and'modeof construction of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I deside to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illusv trated and described.

I Claim:

coal through the conduiti upper fportion, said screw being adaptedv to raise to a jet member at its upper end, thel screw cy a i forwardly flaring hollowwith slots through its sides, and a conveyor thread encircling the hub for the major portion of its length and terminating adjacent the rear end of said flaring portion.

6. A locomotive `stoker conveyor screw forv use in an inclined riser conduit having an enlarged upper portion, said screw beingadapted. to raise coal through ,the conduit toa jet member at its upper end, the screw comprising a hub. having l. A locomotive stoker conveyor' screwv forv use in lan inclined riser conduit havingr an enlarged upper portion, the sc rew comprising 'a hub and a conveyor thread encircling the hub, the diameter of a portion of said thread which isspaced rearwardly from its delivery end and is adapted y 4to be disposed in the enlarged'upper portion of the conduit being materially smaller than the portions `of said thread at both ends of said smaller portion to provide an area in which positive feeding of the coal is reduced'whereby the coal will'mound up andy be. spread laterally by the delivery end portion of the thread.

2. A locomotive vstoker conveyor screw for user in an inclined riser conduit having an enlarged upper portion, the screw comprising a hub having an enlarged delivery end, and a conveyor thread' encircling the hub and enlarged end, said thread being tapered in toward the hub at a location which is spaced rearwardly from the delivery end of the thread and which is adapted to be disposed in `theenlarged upper portion of the coni duit, whereby to provide an area'in which feeding ofthe coal is retarded to permit the coal to mound up and be spread laterally by the delivery end portion of the thread.

3. A locomotive stoker conveyor screw for use in an inclined riser conduit having an enlarged upper portion, said screw being adapted to raise coal through the conduit to a jet member at its upper end, the screw ycomprisinga hub and a conveyor thread encircling the hub for the major portion of its length and terminating short of a forwardly flaring hollow delivery end portion with slots through its sides,a thread encircling saidv end portion,y and a conveyor thread encircling the hub` for the major" portion of .its

length and terminating adjacent the rear end of said flaring portion.

, 7. A locomotive stoker conveyor screw for use in an inclined riser conduit having an enlarged upper portion, said screw being adapted to raise coal throughthe conduit to a jet member at its upper end, the screw comprising a hub having a forwardly flaring hollow delivery end portion with slots through its sides, a conveyor thread encircling the hub for the major portion of its length and terminating` adjacent the rear end of ksaid flaring portion, and a short reverse thread encircling said flaring portion.

8. A locomotive stoker conveyor screw for use 'in an inclined riser conduit having an upper end f portion thatis materially wider than the portion n livery end and is adapted to be disposed in the its deliveryend, the delivery' end'of the screw being formed for pushing the rising coal laterally away from the hub, and the diameter of the screw being reduced between its laterally pushing end portion and said thread whereby to provide an area in said enlarged upper portion of the conduit for coal to mound up in. i l

4. A locomotive stoker conveyor screw for use in an inclined riser conduit having an`r enlarged upper portion, `said screw being adapted to raise coal through the conduit to a jet member at its upper end, the screw comprising a hub having a delivery end portion formed for directing coal.,

laterally, and a conveyor thread encircling the hub for the major portion of. its length and terminating at a point spaced rearwardly from said delivery end portion to provide an intervening area in whichfthe coal will mound up and be spread laterally toward the sidesV of the jet member by said delivery end portion oi the hub.

5. A locomotive stoker conveyor screw for use in an inclined riser conduit having an enlarged of the conduit leading up to it, the diameter of a portion of the screw which is spaced rearwardly from its delivery end and is adapted'to enlarged upper portion of the conduit being materially smaller than the portions of the screw at both ends of said smaller portion to provide an area 1n which feeding of the coal is retarded whereby thev coal will mound up and be spread laterally by the delivery end portion of the screw, and the portion of the screw on both sides of .said smaller portion including conveyor thread flights.

d `10. A locomotive stoker conveyor screw for use in an inclined riser conduit having an upper end portion that is materially wider than ,the portion of the conduit leading up to it, the screw oomprising a hub having an enlarged portion near its delivery end in a location adapted to b e disposed in said wide upper end ofthe conduit, a screw conveyor thread winding around said hub from its lower end to a point adjacent the lower end of said enlarged portion of the hub, and a screwv flight winding around the delivery end portion'of the hubabove said enlarged portion thereof.

SAMUEL G. JONES.

rising a hub having. elivery end portion 

